There is a known medical device for quickly and easily performing a cutting procedure for a site in the airway, such as the pharynx (for example, see PTL 1).
In this medical device, a rotational force applied through the operation of a handle provided at the proximal end of a rigid insertion portion is transmitted, by a drive shaft passing through the insertion portion, to external gear at the distal end of the drive shaft, thus rotating, at the distal end of the insertion portion, a rotation unit that is provided with internal gear engaged with the external gear.